By: Software Engineer Tehreem Awan
A firewall is an online security measure to protect your computer from viruses and other malicious attacks. You can use the internet to communicate with around 4.9 billion people worldwide. The downside is that everybody also has access to you. This includes hackers and viruses that want to steal your data, take control of your computer or even destroy it. To stop this from happening, a firewall controls the data flowing between your computer and the internet. A firewall inspects data to make sure it has the right permissions. If it does, it can pass through.
A Virtual Toll Gate
A firewall works at your computer’s ports. When we’re talking about computer networking, a port isn’t the same as a jack or socket you plug your monitor into. Rather it’s a virtual entry point where your computer exchanges information with other networks. Every computer has lots of ports, each of which handles different kinds of data. For instance, according to the Internet Measurement Conference (IMC), emails often go to port 25 while webpages go to port 80 — even though they both come through the same internet connection
How it Works ?
When a firewall checks if data can enter your network, it’ll read a message that comes with it called metadata. This will list a string of numbers indicating where the data has come from (known as the source address), where it’s going (the ‘destination address’ aka your PC) and over which port. Whether the data has permission will all depend on a set of rules known as a protocol. These rules can be set to prevent you — or any other particular user – from uploading certain files to the internet.
Data Packets: The Atoms of The Internet
A video file isn’t sent from YouTube to your computer as a single file. Instead, it’s broken down into smaller pieces called data packets, which reassemble once you receive them, according to the website security company Cloudflare. Packet-filtering firewalls will check each data packet to make sure it has permission to pass through your network.
